Conventionally, an image reading device structured to read an image of a reading object has been known (see, for example, International Publication No. WO 2014/129152). The image reading device described in the above-mentioned patent literature includes a cover glass on which a reading object is placed. A light source element and a light guide body for irradiating a reading object with light emitted from the light source element are disposed on a lower side of the cover glass. Further, an imaging-forming optical system and a sensor IC are disposed under the cover glass. The image reading device reads an image of an under face of the reading object which is placed on the cover glass.
The present inventor has examined a structure of an information reading device which is capable of optically reading information on one face of an information recording medium and then optically reading information on the other face of the information recording medium even through the information recording medium is not taken out and then insert again. In other words, the present inventor has examined a structure of an information reading device which is capable of optically reading information on both sides of an information recording medium without performing taking-in and taking-out of the information recording medium. In the image reading device described in the above-mentioned patent literature, in order to optically read information recorded on both sides of an information recording medium without performing taking-in and taking-out of the information recording medium, it is sufficient to additionally provide illumination for irradiating an upper face of the information recording medium placed on the cover glass with light and an optical system and the like for reading information of the upper face of the information recording medium.
In a case that information of an under face of an information recording medium is to be optically read, for example, when a width in an upper and lower direction of an insertion port of an information reading device for the information recording medium is set as narrow as possible, influence of external light (disturbance light) on an image of the under face of the information recording medium read by the information reading device can be restrained. However, the present inventor has found through examinations that, in a case that information of an upper face of an information recording medium is to be optically read, even when the width in the upper and lower direction of the insertion port is narrowed, an image of the upper face of the information recording medium read by the information reading device is easily affected by external light.
When a width in the upper and lower direction of an insertion port is narrowed, an information recording medium is hard to be inserted into the information reading device. Further, in a case that a width in the upper and lower direction of the insertion port is narrowed, an image of the upper face of the information recording medium is easily affected by external light. Therefore, the present inventor has examined that a width in the upper and lower direction of an insertion port is widened in consideration of operability when the information recording medium is to be inserted into the information reading device, and that a light shielding member is provided on a front face side of the information reading device for restraining influence of external light on an image of the information recording medium read by the information reading device.
The present inventor has found that, when a light shielding member is provided on a front face side of the information reading device, influence of external light on an image of an upper face of the information recording medium read by the information reading device can be restrained. Further, the present inventor has found that, when a width in the upper and lower direction of an insertion port is widened, an image of an under face of an information recording medium is easily affected by external light. However, the present inventor has found that, when a light shielding member is provided on a front face side of the information reading device, influence of the external light on an image of the under face of the information recording medium can be also restrained.
However, the present inventor has found through examinations that, in a case that a light shielding member is provided on a front face side of the information reading device, an inside of the information reading device becomes hard to be seen by the light shielding member and thus, when an information recording medium is inserted into the information reading device, the information recording medium in an inside of the information reading device is hard to be confirmed by visual observation, and it is difficult to confirm by visual observation whether the information recording medium is placed at a predetermined position of a cover glass or not. In order to solve the problem, it may be conceivable that, when an information recording medium is to be inserted into the information reading device, the light shielding member is turned or the like to retreat to a position where the information recording medium in the inside of the information reading device can be confirmed by visual observation. However, each time an information recording medium is inserted, when the light shielding member is retreated to a position where the information recording medium in the inside of the information reading device can be confirmed by visual observation, operability of the information reading device is deteriorated.